Self-extinguishing composite laminate

ABSTRACT

This invention relates to a self extinguishing composite laminate which combines flexibility and light weight with high tensile-and tear strength and a high degree of flame resistance. This result has been attained by combination of previously known fire resistance agents so that the different components of the laminate each carries a set of flame resistance composition, designed not only to give the component in itself a high flame resistance, but also with regard to maximizing the synergistic effect with adjacent layers as well as between different chemical compounds. A range and system of composite design has been found, which in a surprising manner makes possible the construction of flexible foldable light weight laminates combining substantially retained strength properties, with a degree of flame resistance not previously attained particularly with olefinic materials without major sacrifice of structural properties.

1 Aug. 19, 1975 1 1 SELF-EXTINGUISHING COMPOSITE LAMINATE [75] Inventor: Wei-Gwo Chen, Houston, Tex.

[73] Assignee: Griffolyn Company, Inc., Houston,

Texv

22 Filed: Mar. 26, 1973 211 Appl.No.:344,499

[52] U.S. Cl. 428/110; 428/339; 428/441; 428/474; 428/483; 428/516; 428/921 [51} Int. Cl..... B32b 3/14; B321) 17/04; B32b 27/12 [58] Field of Search 161/191, 403,143,151, 161/158, 168, 182, 256, 254, 165, 170, 227,

Primary limmlnerGeorge F. Lesmes Assistant Examiner-Ellis P. Robinson Attorney, Agent, or FirmW. F. Hyerpv Eickenroht arjvin B.

[57] ABSTRACT This invention relates to a self extinguishing composite laminate which combines flexibility and light weight with high tensile-and tear strength and a high degree of flame resistance. This result has been attained by combination of previously known fire resistance agents so that the different components of the laminate each carries a set of flame resistance composition, designed not only to give the component in itself a high flame resistance, but also with regard to maximizing the synergistic effect with adjacent layers as well as between different chemical compounds. A range and system of composite design has been found, which in a surprising manner makes possible the construction' of flexible foldable light weight laminates combining substantially retained strength properties, with a degree of flame resistance not previously attained particularly with olefinic materials without major sacrifice of structural properties. I

2'Claims, 9 Drawing Figures PATENTED AUG 1 9 I975 SE-IKET 3 [1F 3 SELF-EXTINGUISHING COMPOSITE LAMINATE BACKGROUND OF THE INVENTION For packaging of bulky, flame sensitive substances, such as for example cotton bales, it is highly desirable to have available a low cost light weight, high strength wrapping material which is of sufficiently flame resistance not to ignite, or permit access to the wrapped cotton, of such small fire sources as a burning cigarette, or a superficially applied partly burned match thrown onto its surface.

For protection of building sites to permit all weather construction, it is likewise highly desirable to have a low cost laminate which will resist a quick spark-like contact with a thrown match or cigarette or even a welding spark.

Numerous attempts have been made to meet these needs, but they have not been successful commercially. In the trade, polyvinyl chloride films have been used in spite of the drawbacks of cracking at low temperatures, higher costs, heavier weights, and gradual stiffening due to the slow evaporation of plasticizers. Attempts to retain strength in the lower cost olefinic films made fire resistant by conventional use of known fire resistant agents have been uniformly unsuccessful.

OBJECTS OF THE INVENTION An object of the invention is a low cost high strength laminate of sufficient fire resistance to survive a fire contact with a thrown match or cigarette or similar spark.

Another object is a protectant screen for cotton bales and similar large packages of combustible materials easily ignited by a casual spark.

Another object is a protective screen for building sites, and the like.

Further objects will become apparent as the following detailed description proceeds.

PRIOR ART The following list summarizes the present state of the art:

Baitinger, William F.: Cellulose Reactive Fire Retardants. J. American Assoc. Textile Chemists and Colorists 4, No. 7, 15-19 (July 1972), 38 refs.

Coplan, M. J.: Flammability Treatments for High Performance Textile Fibers. Textile Information Sources and Resources 5, No. 4, -11 (1972).

Daigle, D. M.: THP-Amide Flame Retardant for High Quality Childrens Sleepwear. Textile Information Sources and Resources 5, 17-18 (1972).

Daigle, D. J.: Pepperman, A. B.: Drake, G. L.: Reeves, W. A.: THP-Amide Flame Retardant for High Quality Childrens Sleepwear. 3-page paper presented by D. J. Daigle at the 12th Cottom Utilization Research Conference, 1972.

Daigle, D. J.; Pepperman, A. B.; Drake, G. L.; Reeves, W. A.: A Flame-Retardant Finish Based Upon Tris (hydroxymethyl), Phosphine. Textile Research Journal 42, No. 6, 347-353 (June 1972), 14 refs.

Drake, George L., Jr.: Fire Retardancy: Its Status Today. American Dyestuff Reporter, 60, No. 5, 43-47 (May 1971 27 refs.

LeBlanc, R. B.: Fire-Retardant Finishing of Polyester-cotton Blends. Textile Information Sources and Resources 4, No. 7, 25-26 (1971), (R720l709). Paper presented at 162nd National Mtg., ACS, Washington, DC, Sept. 12-17, 1971.

Linden, P.; Roldan. L. G.; Sello, S. B.; Skevronek, H. 8.: Flame Resistance of Polyester/Cellulosic Blends. Textilveredlung 6, No. 10, 651-656 (Oct. 1971 (R7201718).

Lyons, J. W.: Mechanisms of Fire Retardation with Phosphorus Compounds: Some Speculation. Journal of Fire and Flammability 1,302-31 1 (Oct. 1970),.10 refs (R720 1 721 Nametz, R. C.: Flame-retarding synthetic textile fibers. Industrial and Engineering Chemistry 62, No. 3, 41-53 (March 1970), 107 refs.

Vigo, T. L.: Reaction of Cotton Cellulose with Phosphorus Trihalide-DMF Systems as an Experimental Approach to Flame-retardant Fabrics. Textile Information Sources and Resources, 5, No. 5, 10-11 (1972).

BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention, I use a basic grid of a noninterwoven geometric pattern of high strength fibers of not excessively fire sensitive polymeric material. Surprisingly, I have found that polyamide fibers are sufficiently pyrophobic to be admissible as reinforcers in a system where each fiber is surrounded with an adhesive charged with fire retardants adequate to impart protection also for these particular fibers and the olefinic boundary films are protected with a fire retardant combination which on contact with heat keeps it together for a long enough time to prevent damage to the fibers from casual sparks and similar short time exposure contacts with a flash of fire. The degree of sacrifice of strength in the olefinic films is compensated for by the high strength of the fibers, and the necessary extensibility of the composite is attained by coaction of the properties of the three components, as adjusted within the ranges stated below.

THE DRAWINGS FIG. 1 is a perspective view.

FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6 are sectional side views, taken in the longitudinal direction through a lower bundle of reinforcing fibers.

FIG. 7 is a top view.

FIG. 8 and FIG. 9 are perspective views.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1, 2, and 3, Fibers 1 and 2 are two layers of fibers which may or may not be chemically identical, which are noninterwoven and preferably noninterlocked, so that when exposed to mechanical force, the fibers can slide within the composite structure of which they are a part.

These fibers are made of an orientable structure having a strength in excess of l denier/gram or a carrying strength of at least 500 grams per fiber bundle. The material of which they are made is selected from the group of materials which consists of linear polyamides and polymers of halogen containing monomers in which the halogen content is at least 10%, or polyester fibers containing a fire retardant halogen content. Thus they have a degree of flame resistance which is not less than that of the polyamides together with an appreciable reinforcing strength.

These fibers are covered with a compound 3, the composition of which is further discussed below and which will critically contribute to the fire protection of the fibers. This can be important because reinforcing fibers can carry the fire from one segment of the laminate to another if temperature conditions are such that the film material melts away, while the fibers have a cant continuity of, unprotected stretch is avoided. Generally, the total volume of adhesive in the laminate should be at least 10% and preferably 50500% of the total volume of the fibers present.

higher softening temperature and remain intact. This From a functional standpoint it is preferable that the condition is particularly likely to occur when the film entire space between fil 4 d 5 i filled b h en$ iSt5 of a llght Welght P y y film and the reinbined volumes of fibers and adhesive, however, this is forcmg fibers of a pelyamlde or Particularly of y e from a performance standpoint overprotective and Nametz stetes the most recent eomprehensfve often unnecessary, so that as a practical matter, some Summary on thls SubJeet (Indusmal and Engmeerlng economy on the adhesive may be practiced permitting Chemistry, VOL 3, P g 47, COL 2 lines some attenuation of the adhesive so long as the fibers (1970)? date, no truly effeetlve flame retarflent are adequately covered and the films and fibers adefielshes for nylon have been developee T eendltlon quately adhered. Herewith, I mean that the laminate lllustratedl 5 and i e should function adequately as such in each given set of 4 shews an melplem fi Started In the Proxlmny of a circumstances. Preferably the adhesive should hold the Weldmg J from a y Spark 5 Shows the laminate together under normal conditions of use, and lard exlsnng Wlth a lammate eomemmg unpreteeted under overstress should permit the fibers to slip within 420 denier nylon fiber bundle consisting of 60 individthe laminate so as to bunch and form a rope along the ual fibers with a per bundle tensile strength of approxi incipient tear thus limiting the Spread of damage as mately where the spark P enfmgh heat lustrated in FIG. 7 where an instrument 8 has pierced pierce the laminate and leave fire in its trail. The contithe laminate and a moved in the direction of the nuity and expansion 9 fire is Caused by e propagation row. The fibers have bunched and formed a rope, thus of fire across a gap in the film where this has melted, preventing further damage to the laminate m e e e the fact F the fi 1m,ltSelf eontamed e Thus, the resultant article is a flexible foldable plastic extmgulshleg matenel to the of e the meeham' laminate comprising high strength oriented reinforcing ea] propernee permuted (5% of ehlormated paraffin fibers. A fire resistant adhesive greatly enhances the and of ammeny oxlde) lnueiretes the corre' fire resistance not only of the skins, 4 and 5, but also Spondmg .Stage of a otherwlse Slmllar to that of of the reinforcing fibers. The skin is protected because wlth the exceptlon that the nylon fibers were the adhesive inherently wets the skin otherwise it surrounded and embedded in an adhesive, which comcould not adhere Thus when the adhesive adjacent to prised as a softening and tackifying agent in its formulathe Skin is warmed y i local Spark or incipien fire, it tion as well as for fire retardant properties, 5 to 15% of liqufies Due to its wetting property it then Spreads "ls-halogenated propyl phosphate The heat softened over the inner face of the heated film. This alone often mass 7 of adhesive 3 in FIG. 6 prevents the fire from th h t th 1 at suffices to extinguish a fire at its very incipiency, ust

propaga mg mug e a m as the first breakthrough through the outer skin is The formulation of the adhesive employed was as folabout to be made. At least as important, however, is lows, parts being by weight: that the fire resistant adhesive permits the use in these Ethylene dichloride 2 Ethyl acetate 20 Solvents n-hexane/ 73 Ethyl acrylatc 65 i l Butyl acrylate PC 3 f i 75 Laminatirig 25 Process 83 i 17 Antimony oxide or In the Figures, 4 and 5 are the two outer films of the laminates of fibers which have high strength and highly desirable resiliency properties, (30% elongation in nylon) but whose fire propagating properties are marginal as for example in nylon or most polyester fibers, or even nonexisting as in for example olefinic fibers such as polypropylene which could not properly be used at all in the fire resistant laminates, except in conjunction with the fire resistant adhesive present in amply adequate quantities to cover such potentially burnable fibers completely. The overall fire resistance is of course beneficially influenced by the use of fire resistant films and fibers as well, however these seldom if ever suffice to accomplish the optimal degree of fiber resistance unless plasticized to the point of questionable stability and aging properties, and/or substantially increased cost. Fire resistant polyester fibers may be employed such as esters of endo ehloro or bromo methylene tetra hydro phthalic anhydride and/or halogen containing glycols.

Glass fibers preferably coated with a fire resistant polymer may also be used for reenforcement.

The invention is further illustrated by the following examples, which are presented to illustrate the invention with a few representative applications, and not in any sense of limitation.

EXAMPLE 1 Multifilament fiber, containing 60 filaments per strand, of strength 7 grams per denier, tensile strength was strung up on pegs, arranged as shown in FIG. 10. This fiber remains oriented up to a temperature of 300F. A fire retardant adhesive of the following formula was prepared; the parts in this, and the following examples being by weight:

multipolymer acrylic concentrate 100 (80% solid content) tris-halogenated propylphosphate antimony trioxide 5 The multipolymer acrylic concentrate was prepared from copolymerization of 5.2 parts of acrylic acid and 83 parts of butyl methacrylate, in a volatile hydrocarbon solvent, using benzoyl peroxide as catalyst, from which the solvent was subsequently distilled so as to leave an adhesive containing 80% solid.

Such an adhesive is being sold by the Griffolyn Company, lnc., Houston, Texas under the trade name Griffobond 47.

Another usable adhesive is sold by the Rohm and Haas Company under the trade name Acryloid; still another usable adhesive is being sold by the Catalin Division of Celanese Company, Inc. of New Jersey. While any permanent, somewhat tacky or rubbery adhesive may be used to some degree, the above resins appear to possess favorable combination of resiliency, adhesiveness and tack for the practice of the present invention.

This adhesive was thoroughly mixed and dispersed in a proper solvent at solid content level and was then applied to the resultant nylon fiber grid and allowed to dry, so that the fibers were wetted and the sol vent evaporated, leaving the fibers connected by the resultant soft and somewhat resilient fire resistant adhesive. The same adhesive was rolled onto a 2-mil film of low density polyethylene having a melting point of about 200F. When most or all of the solvent had evaporated from this adhesive, the nylon fibergrid was cut loose and superimposed onto the film. Additional adhesive was sprayed onto the film using 1.0 grams of the adhesive per ft of film, and was likewise sprayed onto a l-mil polypropylene-polyethylene copolymer film having a tensile strength of 4 lb/in strip and an elongation of 300% and a melting point of 250F. Upon drying, this second film was turned with the adhesive side downward and laminated to the first mentioned film and the nylon layer by means of a handroller 11 as shown in FIG. 11. The resultant film showed a fire resistance when tested by horizontal burning method.

EXAMPLE 2 A laminate was prepared as in Example 1 using as the outer skin 4 a 3-mil low density polyethylene film and as the inner skin 5 a 3-mi1 thick dioctyl phthalate plasticized polyvinyl chloride film 5, and as the adhesive the acrylate base of Example 1 compounded with 8% of a C1 chlorinated paraffin wax and 3% antimony oxide. The fiber grid consisted of two non-woven layers of 420 Denier nylon, composed of filaments. The quantity of adhesive was 23% of the weight of the total laminate. The resultant laminate showed a fire resistance sufficient to make the film self-extinguishing in 4 seconds flame out time by ASTM testing method D- 568.

EXAMPLE 3 A laminate was prepared as in Example 1, using as outer and inner skins l to 5 mil of low density copolymer of ethylene and polyvinyl acetate, known in the trade as Elvex and sold by the E. I. duPont deNemours and Co. Positioned between the films was a diamond shaped nonwoven grid of slidable fibers, positioned in two parallel groups spaced about inch between the parallel fibers in each of the two crossing layers of the grid. The films and fibers were held in position by an adhesive comprising as a principal ingredient butyl acrylate and containing 5% of either stabilized chlorinated wax or antimony trioxide. The fibers were flat polypropylene split into ribbonlike filaments at least 10 Deniers and preferably l560 Deniers.

The quantity of adhesive employed was sufficient to leave a continuous coating over the entire film contact area, including the fibers. On test, the laminate was found self extinguishing, the elongation of the films exceeded that of the fibers, so that on tear, the strength of the fibers of the aggregate was controlling.

EXAMPLE 4 A laminate was prepared on a commercial two roller continuous lamination machine, in which a scrim of 600 Denier polyester fiber, spaced /2 inch apart, was fed and laminated between 3-mil two polypropylene films, using as the adhesive a compound of 80 parts by weight of butyl acrylate and 20 parts of a polyurethane prepared from stochiometric proportion of ricinoleic acid and tetraethylene isocyanate, in which was compounded as fire resistance agents, 5 parts of a 60% chlorine substituted paraffin wax and 5% of tetrakis (2- cyanoethyl) phosphonium bromide. The adhesive layer added 2 mil to the total polymer thickness. The resultant laminate did not support combustion and had the requisite overall tear and support strength expected of building tarpaulins.

EXAMPLE 5 A laminate was prepared as in Example 1, using as the film a copolymer of 80% ethylene and 20% difluoro ethane, which in itself was not self extinguishing, though it burned substantially slower than polyethylene. This film, 3-mil thick, was reinforced with a scrim in which the longitudinal fibers were of 300 denier glass fibers coated with a light surface layer of neloprene, a chlorinated elastomer made by the E. l. duPont deNemours and Co., and the transversal fibers were of polyethyleneterephthalate (Dacron) of 400 denier. The adhesive was an acrylic multipolymer adhesive comprising parts of acrylic acid; 50 parts of ethyl acrylate, 30 parts of methyl methacrylate, and 6 parts of amyl acrylate copolymerized in 500 parts of hexane using 1% of benzoyl peroxide, the nonvolatiles, as the catalyst, and 100 parts of ethylene chloride, and further containing, as fire preventives, 3% on the nonvolatile content of tris (hydroxymethyl) phosphine and 5% each of 60% chlorinated paraffin wax and of liquid chlorinated wax Diablo made by the Diamond- Shamrock Chemical Company.

The resultant laminate was self extinguishing by the test ASTM-568. The laminate was transparent and had ample strength, since the plastic film had an elongation in excess of the fiber system, and thus received full structural support of the latter.

EXAMPLE 6 A laminate was prepared as in Example 1, using an upper film of high density isotactic ethylene-propylene copolymer, lO-mil thick, and a lower film of polybenzimidazol, 2-mil thick with a reinforcement of nonwoven continuous 10 denier nylon filaments with an average distance between filamants of one millimeter.

Between these films was deposited a 2-mil thick layer of an adhesive consisting of 4 parts of 1,3 (trisbromo isopropyl) ortho phosphate, 2 parts of dibutyl ortho antimonate and 24 parts of polybutyrolactone.

The resultant laminate had a total thickness of mil, and was fire resistant.

While certain specific components and ingredients have been mentioned in the above description and in examples, these may be modified or substituted without departure from the essence of this invention. The outer films 4 and 5 consist essentially of olefinic polymers, preferable because of low cost, good general mechanical properties and superior resistance to embrittlement or cracking at low temperatures. While some other film could be substituted for film 5, the outer film 4 should preferably be polyolefinic. If enough fire resistant materials were incorporated in this film to protect the laminate, the mechanical properties of the composite would suffer excessively. While it has been found that a certain degree of fire resistant substances is indis' pensable in this film, a far lesser degree of fire resistance is necessary than otherwise will suffice if the adhesive adjacent to the film is charged with fire resistant substances compatible with said adhesive. The phosphonium type fire resistant agents are preferred be cause these can be used as plasticizers in the adhesive composition, where they contribute to the desired degree of softness and tack, while in the film their mechanical effect would be wholly detrimental. Other fire resistant agents may be used, for modifying the adhesive fire resistance properties, but appear far less desirable; such are for example borates, antimony oxide and chlorinated waxes and fluorocarbons. The adhesives are compounded to wet the films well. Thus, the fire resistance agents present in the adhesive will immediately upon melting of the adhesive spread with this over the inner surface of the heated film, and effectively reinforce the protection at the most critical point, to the point of aborting the incipient fire.

, Similarly, if the fire has developed to the point of fusing the surface film, the fusion with the adhesive is to prevent ignition of the melt, and in any event, the cov erage of the reinforcing fibers by the adhesive will prevent the spreading of the fire across gaps in the film by fire propagation along these fibers. It is desirable that the various fire resistance additives in adhesives as well as in the films should be able to enhance each other to achieve the synergistic effect. It is this combination of both fire resistance systems in films and adhesive making possible the high performence of the final laminate.

With the adhesive properly charged with fire resistant agents, the fibers will be protected to a significant degree, even if they are not in themselves fire resistant. I prefer to use nylon type fibers because of the high degree of resilience, which is favorable in matching the properties of the light weight films which easily shift form to conform with mechanical tensions encountered. Nylon has a degree of fire resistance which in conjunction with the adhesive formulation of the present invention makes nylon fibers usable in my laminates without the need for any modification of the fiber itself which would impair any of the mechanical properties as a trade-off for increased fire resistance. If I use polyolefin fibers in the laminates, 1 may also rely entirely on the adhesive formulation, particularly if the weight of the adhesive in the laminate exceeds the weight of the fibers, and the loading of fire resistance agents in the adhesive amounts to at least 10% of the weight of the adhesive plus the weight of otherwise unprotected fibers. If at least 4% of tris (2,3-dibromo propyl) phosphate or its analogues is incorporated in a polypropylene polyethylene, or olefinic copolymer fiber, the mechanical properties of the fibers still remain fairly good, and the supplementation of protection by the adhesive as discussed, will prove adequate for the most practical purposes. Polyacrylonitril fibers can be used as a substitute for the nylon fibers, polybenzimidazol or Nomac fibers can also be used, though expensive copolymers containing some halogen, (bromine being the most efficient) likewise may be used, but are not preferred because their generally inferior stability and lower extensibility for the same ultimate strength.

Many fire retardant agents not specifically mentioned in the examples have been tested and found suitable for the application of this invention. The halogenated wax components may be either solid or liquid provided that their halogen content is sufficient to result in a halogen content of at least 5% of the final component in which they are incorporated, for the purposes of fire retardancy, and at least 2% for coaction with other ingredients to effect an overall degree of fire retardancy. A liquid halogen compound found suitable is, for example, one known as Diablo OX sold by the Diamond Shamrock Chemical Company.

Any of the halogens may be employed in these compounds, at cost basis under present market conditions chlorine is the most economical of these, and bromine the most effective on a weight basis.

Among the organic phosphorus compounds, I may use in addition ethylene bis (2-cyano ethyl) phosphonium bromide, tris (hydroxy methyl) phosphine, and their analogues, particularly those with fewer than 7 carbon atoms, unless halogenated, and halogen containing organo phosphorus compounds manufactured by Monsanto Chemical Company, St. Louis, Missouri under the trade name Phosgard and by Michigan Chemical Company, St. Louis, Michigan under the trade name, Fire Master. Of this family of com pounds Fire Master 713 is said to be a tris-halogenated propyl phosphate containing both chlorine and bromine and T-33p is tris (1,3, dichloroisopropyl) phosphate.

Other halogenated alkynol phosphates may be employed.

Among polyesters, usable both as ingredients in the adhesive and as components of fibers, these can be made suitably synergistic to the fire retardant effect of a spreading adhesive by using in their manufacture a minor percentage of chlorendic anhydride (tetra chloro endomethylene phthalic anhydride) or of halogen substituted glycols such as those manufactured particularly by the Wyandotte Chemical Company.

Generally, a halogen content in the components of 25% can be effected without significantly disturbing the mechanical strength properties of these or of the ultimate laminate. This is not sufficient to impart adequate fire resistance to the laminates by itself, but I have found that it increases the susceptibility of these components to the added fire resistivity of the adhesive, so that this becomes the decisive factor in enhancing the overall laminate fire resistance properties to a degree providing adequate practical protection, without materially affecting the mechanical strength properties.

With regard to the antimony oxide component, I prefer to employ antimony trioxide, but may use any antimony compound which on heating fuses to form a spreading coating which bars oxygen from the burning article. This includes also esters such as ethyl and butyl antimonates.

When the reinforcing fibers here employed are in themselves readily combustible, such as olefinic fibers, including the ribbonlike fibers of split polypropylene or polystyrene, it facilitates the attainment of perfect fire retardancy if these too contain such synergistic minor amount of fire retardant compound as can be incorporated without substantial loss of mechanical properties. For the polyolefins this is generally 2 to about 4 or 5% of a compatible halo phosphonium compound; for the styrenes incorporation of a halogen substituted polystyrene is helpful. Particularly the ring Substituted polystyrenes are stable and can be incorporated up to 50% and more, though for economical reasons about 25% generally preferred. The less combustible fibers, such as fibers of polyamides or polyimidazoles, require less if any of these ingredients.

In the adhesive formulation I prefer to use the acrylates as carriers, because of their high stability and consequent good aging properties. Suitably plasticized ester resins, and other glue components familiar to the art may also be used, with the incorporation of the fire retardancy components disclosed above. In addition to the acrylate components already mentioned, or in their place, I may also use for example ethyl methacrylate, dinonyl methacrylate and tri decyl methacrylate, and amyl acrylate.

Still other compounds and their use are known to the prior art, as set forth in the references listed at the beginning of the present disclosure. While these references have shown many methods of effecting fire resistance, none of these has resulted in a translucent laminate of high strength, such as is needed to provide protection for construction crews working on high rise buildings under extreme weather conditions.

Having thus described my invention I claim:

1. As an article of manufacture, a flexible foldable plastic laminate comprising a grid of non-woven oriented reinforcing fibers selected from the group consisting of polyamides, polyesters, polyolefins, glass, polymers from halogen containing monomers in which the halogen content is at least 10%, polyester fibers containing a fire retardant halogen content and polyimidazoles having a melting point higher than the melting points of the outer films of said laminate, said films consisting of polyolefin films each less than 1 1 mil thick and each having incorporated therein as a fire retardant chlorinated paraffin and antimony oxide, the surfaces of said fibers and the inner surfaces of said films being essentially covered, and mutually united, by an organic adhesive having incorporated therein as a fire retardant a halogenated lower alkyl phosphate and antimony oxide, said fire retardants being present in said films and said adhesive in sufficient quantity that the laminate formed thereof is self-extinguishing.

2. An article of claim 1 wherein said films each contain at least 4% of chlorinated paraffin and at least 2% of a substance selected from the group of substances comprising antimony trioxide and substances which on combustion form antimony trioxide. 

1. AS AN ARTICLE OF MANUFACTURE, A FLEXIBLE FOLDABLE PLASTIC LAMINATE COMPRISING A GRID ON NON-WOVEN ORIENTED REINFORCING FIBERS SELECTED FROM THE GROUP CONSISTING OF POLYAMIDES, POLYESTERS, POLYOLEFINS, GLASS, POLYMERS FROM HALOGEN CONTAINING MONOMERS IN WHICH THE HALOGEN CONTENT IS AT LEAST 10%, POLYESTER FIBERS CONTAINING A FIRE RETARDANT HALOGEN CONTENT AND POLYIMIDAZOLES HAVING A MELTING POINT HIGHER THAN THE MELTING POINTS OF THE OUTER FILMS OF SAID LAMINATE, SAID FILMS CONSISTING OF POLYOLEFIN FILMS EACH LESS THAN 11 MIL THICK AND EACH HAVING INCORPORATED THEREIN AS A FIRE RETARDANT CHLORINATED PARAFFIN AND ANTIMONY OXIDE, THE SURFACES OF SAID FIBERS AND THE INNER SURFACES OF SAID FILMS BEING ESSENTIALLY COVERED, AND MUTUALLY UNITED, BY AN ORGANIC ADHESIVE HAVING INCORPORATED THEREIN AS
 2. An article of claim 1 wherein said films each contain at least 4% of chlorinated paraffin and at least 2% of a substance selected from the group of substances comprising antimony trioxide and substances which on combustion form antimony trioxide. 